Trench device and method

ABSTRACT

A catwalk is provided for use in trenching operations that provides increased safety and improves efficiency. Methods are also provided that save time over the prior process of building multiple land bridges. Selected features include reduction in the number of ladders used increases worker safety, along with several other safety features such as catwalk railings, holding devices for ladders, etc. One catwalk is shown with a skid assembly to further increases efficiency by allowing the trench box to be towed with the catwalk in place. A manhole catwalk is shown for easy and safe inspection of manholes without the need for ladders.

PRIORITY APPLICATIONS

This patent application claims the benefit of priority, under 35 U.S.C.Section 119(e), to U.S. Provisional Patent Application Ser. No.60/743,171, filed on Jan. 25, 2006, which is incorporated herein byreference.

TECHNICAL FIELD

This invention relates to walkways that allow access from one locationto another. Specifically, this invention relates to catwalks from anedge of a trench to items within the trench.

BACKGROUND

FIG. 1 shows a common trench 100. Trenches are used for a variety ofpurposes such as utility installation. Some examples of utilitiesinclude, but are not limited to, sanitary sewer, storm sewer, watersupply, gas, electric, etc. A trench box 110 is commonly used whenconstructing trenches 100 to keep the sides of the trench 100 fromcaving in during construction.

During construction, workers must move in and out of the trench 100.Currently, workers construct a land bridge 120 from dirt and lower afirst ladder 130 to the land bridge 120. A worker must go down the firstladder 130 to the land bridge 120 in order to cross from the edge 102 ofthe trench 100 to an edge 112 of the trench box 110. Then the workermust use a second ladder (not shown) to get from the edge 112, into thetrench box 110. As digging of the trench 100 progresses, the trench box110 must be moved, and a new land bridge 120 must be constructed foreach move of the trench box 110.

In some trenching operations, manholes are installed within the trench.Inspection of manholes is currently difficult. Ladders are currentlyused to get from the bottom of the trench up to the manhole opening. Theladder rungs and/or the top of the manhole are not protected with anysafety rails and the inspector is left in an unstable position.

What is needed is an improved device and method to increase efficiencyand safety during trenching operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a trench box and trench according to the prior art.

FIG. 2 shows a configuration of a catwalk according to an embodiment ofthe invention.

FIG. 3 shows another configuration of a catwalk according to anembodiment of the invention.

FIG. 4 shows an end view of a catwalk according to an embodiment of theinvention.

FIG. 5 shows a detail view of a catwalk according to an embodiment ofthe invention.

FIG. 6 shows another detail view of a catwalk according to an embodimentof the invention.

FIG. 7 shows a manhole in a trench with a catwalk assembly according toan embodiment of the invention.

FIG. 8 shows a top view of a portion of the catwalk assembly from FIG.7.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown,by way of illustration, specific embodiments in which the invention maybe practiced. In the drawings, like numerals describe substantiallysimilar components throughout the several views. These embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the invention. Other embodiments may be utilized andstructural, or logical changes, etc. may be made without departing fromthe scope of the present invention.

FIG. 2 shows a catwalk 200 that bridges a gap between an edge 102 of atrench 100 and an edge 112 of a trench box 110. In one embodiment, thecatwalk 200 includes multiple sections. In one embodiment, the multiplesections are hinged together to accommodate multiple possible trenchconfigurations. FIG. 2 shows a first section 202 and a second section204 with a hinge joint 203 between them. A third section 206 is furthershown with a hinge 205 between the second section 204 and the thirdsection 206. In one embodiment, each section of the catwalk 200 includeshand rails. In one embodiment, the catwalk is fabricated from weldedsteel, although the invention is not so limited. Other configurationsinclude alternate materials such as aluminum, wood, polymers, etc. Otherfabrication techniques, apart from welding, include fasteners such asscrews, adhesive assembly, pressure fits, etc. Although three sectionsare shown in FIG. 2, other configurations include fewer sections, ormore sections depending on factors such as the trench configuration, thejob site, etc.

A ladder 210 is shown in FIG. 2 to enter the trench box 110 from thecatwalk 200. It should be noted that with the configuration shown inFIG. 2, only one ladder is needed to enter the trench box 110. A diggersuch as a backhoe 220 is further shown for digging the trench 100. Inone embodiment, the backhoe 220 is further used to pull the trench box110 back as the trench progresses.

FIG. 3 shows the catwalk 200 in position along a trench 100 with adifferent profile from FIG. 1. The catwalk 200 in FIG. 2 shows the pivot203 rotated to where the first section 202 and the second section 204but up against each other, creating a continuous flat walking surfacebetween then first section 202 and the second section 204.

FIG. 4 shows a portion of the first section 202 located on the edge ofthe trench. In one embodiment, a skid assembly 400 is included in thecatwalk 200. In one embodiment, the skid assembly 400 includes a slidingportion 402 and a hinge 404. In one method of operation, the skidassembly 400 allows the catwalk to slide along the edge of the trench asthe trench box is pulled. As discussed above, in one embodiment, thetrench box is pulled along by a digging device such as a backhoe asdigging of the trench progresses. One advantage of a skid assemblyincludes efficiency and speed of a trenching operation. In contrast tothe configuration described in FIG. 1, after moving the trench box,there is no need to construct a new land bridge for entry and exit fromthe trench box.

FIG. 5 shows the third section 206 of the catwalk 200 in closer detailas it is attached to the trench box 110. In one embodiment, a fitting207 such as a pair of metal protrusions line up with a side of thetrench box 110. The fitting 207 holds the end of the catwalk onto thetrench box 110 for safety, and to keep the catwalk from falling off thetrench box 110 during a moving operation as the trench progresses. Inone embodiment, the fitting 207 includes a mating feature welded to thetrench box 110 where the catwalk 200 includes an engaging feature thatis adapted to mate with the mating feature on the trench box. In oneembodiment, the mating feature includes at least one section of a metalcylinder that can be pinned to the catwalk.

The hinge between the second section 204 and the third section 206 hasan added advantage in that the first and second sections 202, 204 can befolded up on top of the third section 206 for selected moving of thetrench box 110. In one method, an obstacle such as a tree or power poleprevents the catwalk from remaining extended during a move of the trenchbox 110. In such a situation, multiple sections of the catwalk can befolded up until the obstacle is passed.

FIG. 6 shows a detail of a portion of the third section 206 of thecatwalk 200. In one embodiment, a holding device 209 such as a hook,clamp, etc. is included on the catwalk 200. The holding device 209 canbe used to hold a ladder 210. One advantage of the holding device 209includes safety to prevent the ladder 210 from falling into the trenchbox. Another advantage of the holding device includes the ability tostore items such as a ladder 210 or a shovel during a moving operationof the trench box. Although one holding device 209 is shown in FIG. 6,multiple holding devices are included in other embodiments, for exampleto hold both a shovel and a ladder.

FIG. 7 shows a catwalk assembly 700 for use with a manhole. A manhole720 is shown inside a trench 710. A manhole unit 730 is shown tofacilitate easy and safe inspection of the manhole 720. In oneembodiment, the manhole unit 730 can be used with catwalk sections asdescribed above. The manhole unit 730 includes a floor 732. The floor732 includes an opening 734. As shown in the figure, manholes frequentlyinclude a taper to their structure. In one embodiment, the opening 724in the floor 732 is sized and shaped to pass over a top of the manhole720, and stop when it encounters the tapered portion. A square opening734 is shown in FIG. 7, however the invention is not so limited. In oneembodiment, a circle opening 734 is used. Other geometries such astriangles, etc. are also possible. In one embodiment, a square openingincludes approximately a 36 inch by 36 inch square to fit over a manholewith a slightly smaller diameter.

A network of guard rails 736 is shown around a perimeter of the floor732. The guard rails increase the safety of an inspector or otherworker. A pair of catwalk sections are further shown in FIG. 7. A firstcatwalk section 740 is connected to the manhole unit 730. A secondcatwalk section 742 is coupled to the first catwalk section 740.Connection methods include those described above, such as hingedconnections using bolts, nuts, pins, etc. Using the catwalk assembly 700an inspector can easily pass from an edge of the trench 712 to themanhole 720 and inspect the manhole while maintaining good footing onthe floor 732, and having the benefit of guard rails 736.

FIG. 8 shows a top view of the floor 732 from FIG. 7. The opening 734 isshown within the floor 732. In one embodiment, as shown, the opening iscentered in the floor to allow a user to walk all the way around amanhole during a procedure such as an inspection.

In one embodiment, a first spacer 810 and a second spacer 820 areincluded. In one embodiment, the first spacer 810 and/or the secondspacer 820 are optionally removable. The first spacer 810 is connectedto the floor 732 on ends 812 and 814. The second spacer 820 is connectedto the floor 732 on ends 822 and 824. Removable connection structuresinclude nuts and bolts, etc.

In one embodiment, the first spacer 810 and/or the second spacer 820 areused to selectively narrow or widen the opening 734. As can be seen fromFIG. 7, manholes are typically round and include a tapered portion neartheir top. By inserting or removing spacers within the opening 734, theoriginal width 832 is reduced to a new width 830. In this way, if aparticular manhole has a different taper, or if the height of themanhole unit 730 needs adjusting, a number of spacers can be inserted orremoved until the manhole unit comes to rest in the desired position onthe manhole. Although a pair of spacers are shown in FIG. 8, theinvention is not so limited. In one embodiment, a single spacer is used.In one embodiment, three or more spacers are used.

CONCLUSION

Thus has been shown, a catwalk for use in trenching operations thatprovides increased safety and improves efficiency. The use of a catwalksaves time over the prior process of building multiple land bridges. Areduction in the number of ladders used increases worker safety, alongwith several other safety features such as catwalk railings, holdingdevices for ladders, etc. The use of a skid assembly further increasesefficiency by allowing the trench box to be towed with the catwalk inplace. An optional manhole attachment further adds to the versatility ofthe catwalk during normal trenching operations.

While a number of advantages of embodiments described herein are listedabove, the list is not exhaustive. Other advantages of embodimentsdescribed above will be apparent to one of ordinary skill in the art,having read the present disclosure. Although specific embodiments havebeen illustrated and described herein, it will be appreciated by thoseof ordinary skill in the art that any arrangement which is calculated toachieve the same purpose may be substituted for the specific embodimentshown. This application is intended to cover any adaptations orvariations of the present invention. It is to be understood that theabove description is intended to be illustrative, and not restrictive.Combinations of the above embodiments, and other embodiments will beapparent to those of skill in the art upon reviewing the abovedescription. The scope of the invention includes any other applicationsin which the above structures and fabrication methods are used.

1. A catwalk assembly, comprising: a floor having an opening sized tofit over a top portion of a manhole, wherein the opening is furthersized to slide only a portion of the way down the manhole; a first endof a catwalk for placement on an edge of a trench; and a second end ofthe catwalk for connection to the floor.
 2. The catwalk assembly ofclaim 1, further including guard rails substantially around the floorand the catwalk.
 3. The catwalk assembly of claim 1, wherein the catwalkincludes a number of jointed sections.
 4. The catwalk assembly of claim1, further including at least one spacer to attach within the opening,the spacer changing a width of the opening along at least one dimension.